Field of the Invention
The invention relates to a device for separating or singling sheets piled up so as to form a stack, in a feeder of a sheet-processing-machine, having a transport element with a guiding edge.
Heretofore known devices for separating or singling sheets, which have been piled up so as to form a stack, in a feeder of a sheet-processing machine have a transport element which is constructed as a pivotable flap and functions for transporting one or more sheets, by a pivoting movement, from the stack to a feeder roll of the machine. For this purpose, the respective sheet resting on the top of the stack is pushed along the guiding edge onto a guide face of the transport element which, by subsequent pivoting movement thereof, transports the respective sheet by the leading edge thereof to the feeder roll. Disadvantageously, the contour of the topmost sheet on the front side of the stack, as viewed in the sheet transport direction, is not always flat, so that it is possible for disruption to occur during the transport of the respective sheet from the stack to the feeder roll, for example, because the sheet is in a skewed position. Individual, visual averaging out of the different heights (lower edge region, higher center region) of the stack at the front side by an operator, and corresponding positioning of the stack and, in particular, of the sheet resting on the top thereof, in relation to the guide edge of the transport element does not lead to reliable results with regard to secure and reliable sheet transport from the stack to the feeder roll.
In addition, the published German Patent Document DE 34 11 886 A1 discloses a device having a first and a second detector for establishing the respective height of the front and rear region of a sheet stack or pile.
It is accordingly an object of the invention to provide a device of the type mentioned at the introduction hereto which, in a reliable, exact and repeatable manner, ensures correct separation or singling of sheets piled up to form a stack, in the feeder, and trouble-free transport of the respective sheets from the stack to a feeding roller of a sheet-processing machine.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a device for separating or singling sheets, which have been piled up to form a stack, in a feeder of a sheet-processing machine, having a transport element with a guide edge, comprising a device for matching the shape of the guide edge to the contour of the topmost sheet at a front side of the stack, as viewed in a sheet transport direction.
In accordance with another feature of the invention, the shape-matching device has a transport element which is at least one of elastically and plastically deformable so as to match the shape of the guide edge to the contour of the topmost sheet.
In accordance with a further feature of the invention, the separating device includes a measuring device for determining the contour of the topmost sheet at the front side of the stack.
In accordance with an added feature of the invention, the separating device includes an adjusting device for matching the contour of the guide edge to the contour of the topmost sheet.
In accordance with an additional feature of the invention, the separating device includes a control unit operatively connected to the measuring device and to an adjusting device for matching the contour of the guide edge to the contour of the topmost sheet.
In accordance with yet another feature of the invention, the transport element is formed as an L profile in cross section and, at an end thereof, has a stop crosspiece which is bringable into engagement with the front side of the stack and, at a top thereof, the stop crosspiece has a guide crosspiece formed with a guide face onto which the topmost to sheet is transportable, the guide edge being located at the outside between the stop crosspiece and the guide crosspiece.
In accordance with yet a further feature of the invention, the transport element is formed rigid in the sheet transport direction and, at the stop crosspiece, is provided with a plurality of mutually spaced teeth for assisting in an elastic deformation of the transport element for matching the contour of the guide edge to the contour of the topmost sheet.
In accordance with yet an added feature of the invention, the separating device includes a fixing device for firmly clamping the teeth separately in order to stabilize the contour-matched guide edge.
In accordance with yet an additional feature of the invention, the fixing device is formed with holding openings wherein the teeth are freely positionable and firmly clampable, by deforming the transport element, so as to match the contour of the guide edge to the contour of the topmost sheet.
In accordance with still another feature of the invention, the adjusting device includes a plurality of actuators arranged spaced apart from one another.
In accordance with still a further feature of the invention, the actuators are formed as plungers having a position which is adjustable on a rotatable cam disc.
In accordance with an alternative feature of the invention, the actuators are formed as spindles operatable by a drive.
In accordance with still an added feature of the invention, the transport element is pivotable, between a stop position and a transfer position, about an axis of rotation extending perpendicularly to the sheet transport direction.
In accordance with still an additional feature of the invention, a matching of the contour of the guide edge to the contour of the topmost sheet by the adjusting device is dependent upon a pivoting-angle position thereof relative to the transport element.
In accordance with another feature of the invention, the guide edge is formed so as to be contour-matched to the topmost sheet in the stop position of the transport element and to be straight in the transfer position of the transport element.
In accordance with a further feature of the invention, the transport element is movable selectively counter to and in a respective contour-matching direction by a restoring spring element, respectively, compressible and expandable by the pivoting of the transport element.
In accordance with an added feature of the invention, in the transfer position of the transport element, the restoring spring element is compressed, the transport element is retracted and the contour matching of the guide edge is canceled, while, in the stop position of the transport element, the restoring spring element is expanded, the transport element is extended and the contour of the guide edge is completely matched to the contour of the topmost sheet.
In accordance with a concomitant feature of the invention, the transport element is formed as a continuous, pivotable flap, and the fixing device is formed as a pivoting shaft for the flap.
In order to achieve the objective of the invention, a separating device is proposed having features distinguished by the fact that the shape of the guide edge can be adapted or matched to the contour of the topmost sheet at a front side of the stack, as viewed in the sheet transport direction. This advantageously prevents the leading edge of the topmost sheet, which is generally not straight, but rather, bent downwardly, in particular in the edge regions thereof, from colliding with the guide edge as it is displaced from the stack onto a guide face of the transport element, and becoming skewed in an uncontrolled manner with respect to the sheet transport direction. By adapting or matching the contour of the guide edge to the leading edge of the topmost sheet, correct transport of the respective sheet from the stack to the feeder roll of a sheet-processing machine by the transport element is therefore reliably assured.
It is advantageous, for adapting or matching the contour of the guide edge, that the transport element be elastically and/or plastically deformable. A deformable guide edge is particularly suitable for exact and repeatable adaptation or matching of the contour to the leading edge of the topmost sheet. In this regard, both an elastic, plastic, as well as also a combined, partially elastic and partially plastic deformation of the guide edge is used to adapt or match the contour.
The separating device advantageously has a measuring device for determining the contour of the topmost sheet at the front side of the stack. By using a measuring device, for example, a sensor which can be displaced over the front side of the stack in the direction of the stack width, or a plurality of sensors arranged spaced apart over the front side of the stack in the direction of the width of the stack, it is possible, in a rapid, exact and possibly also continuous manner, to determine the contour of the respectively topmost sheet at the front side of the stack. Based upon these exact determined data, a precise, possibly automatic, adaptation or matching of the contour of the guide edge to the contour of the respective topmost sheet is assured.
The separating device preferably has an adjusting device for adapting or matching the contour of the guide edge to the contour of the topmost sheet. The use of an adjusting device makes it possible, preferably in an automatic manner, to implement exact and repeatable adaptation or matching of the contour of the guide edge to the contour of the topmost sheet. In addition, an adjusting device permanently operatively connected to the transport element permits continuous adaptation or matching of the contour of the guide edge to the contour of the topmost sheet, even during the operation of the separating device, using measured values which are likewise determined continuously.
According to a preferred embodiment, the separating device has a control unit which is operatively connected to the measuring device and the adjusting device. A control unit of this type permits automatic, user-friendly and reliable adaptation or matching of the contour of the guide edge, even during the operation of the separating device, with regard to the contour established, respectively, by the topmost sheet at the front side of the stack. Thereby, in a particularly effective manner, rapid and simultaneously correct transport of the respectively topmost sheet from the stack to the feeder roll of the sheet-processing machine by the transport element is assured.
The transport element is preferably formed as an L profile in cross section and, at an end thereof, has a stop crosspiece which is bringable into engagement or touching contact with the front side of the stack and, at the top thereof, the transfer element has a guide crosspiece onto a guide face of which the topmost sheet can be transported, the guide edge being located at the outside between the stop crosspiece and the guide crosspiece. A transport element constructed in this manner is particularly suitable for forming, on the one hand, a stop for the leading edges of a plurality of sheets resting on the stack at the top or stop crosspiece and, on the other hand, for being used as a transport element for transporting the respectively topmost sheet from the stack to the feeder roll. This transport element is suitable, in particular, for adapting or matching the contour of the guide edge or of the entire guide face by appropriate elastic and/or plastic deformation.
The transport element is advantageously formed rigid in the sheet transport direction and, at the stop crosspiece, is provided with a plurality of mutually spaced teeth assisting in the elastic deformation of the transport element to adapt or match the contour of the guide edge. The transport element, which is formed rigid in the sheet transport direction, is particularly suitable as a stop for the leading edges of the sheets resting on the top of the stack. A stop crosspiece provided with a plurality of mutually spaced teeth permits an exact and precisely repeatable elastic deformation of the guide edge or of the guide face of the guide crosspiece in order to achieve correct adaptation or matching of the contour.
According to an alternative embodiment, the teeth are firmly clampable separately by a fixing device in order to stabilize the contour-matched guide edge. The teeth of the stop crosspiece, which are firmly clampable relatively easily in a corresponding fixing device, are particularly suitable for fixing the adaptation or matching of the contour produced by elastic deformation of the transport element.
The fixing device is preferably provided with holding openings, wherein the teeth are freely positionable and firmly clampable, by deforming the transport element, in order to adapt or match the contour of the guide edge. Through the intermediary of a fixing device constructed in this manner and provided with holding openings, the adaptation or matching of the contour of the guide edge and of the guide face of the guide crosspiece, respectively, is possible in a user-friendly and precise manner. In this case, the elastic and/or plastic deformation of the transport element can be performed by manual setting or else automatically by a suitable adjusting device.
The adjusting device is advantageously formed as a plurality of actuators arranged spaced apart from one another. With a plurality of mutually spaced actuators operatively connected to the guide crosspiece of the transport element, it is possible for individual segments of the guide crosspiece (edge regions, central region) to be deformed elastically and/or plastically in such a way that exact and possibly also continuously adjustable contour-adaptation or matching of the guide edge and of the guide face, respectively, of the guide crosspiece is attainable.
According to an alternative embodiment, the actuators are formed as plungers having a position which is adjustable on a rotatable cam disc. Actuators constructed in this manner are particularly suitable for automatic and possibly continuous adaptation or matching of the contour of the guide edge by an appropriate adjustment of the position of the plungers operatively connected to the transport element.
According to a further, alternative embodiment, the actuators are constructed as spindles operatable by a drive. Spindles which are operated by a drive and are operatively connected to the transport element are also suitable, in particular, for automatic and possibly continuous adaptation or matching of the contour of the guide edge.
The transport element is advantageously pivotable, between a stop position and a transfer position, about an axis of rotation which is perpendicular to the sheet transport direction. A transport element that is movable in this manner is particularly suitable as a stop with respect to the leading edges of the sheets resting on the top of the stack and, simultaneously, as a transport element for rapid and correct transport of the respectively topmost sheet from the stack to the feeder roller of the sheet-processing machine.
The adaptation or matching of the contour of the guide edge by the adjusting device advantageously depends upon the pivoting-angle position with respect to the transport element. Because the contour-adapted or matched guide edge is used in particular to ensure reliable and correct displacement of the topmost sheet from the stack onto the transport element (guide face), the adaptation or matching of the contour of the guide edge does not necessarily have to be maintained until the corresponding sheet is transferred to the feeder roller. It may therefore be advantageous to change the contour of the guide edge depending upon the respective pivoting angle of the transport element.
The guide edge is preferably constructed so as to be contour-adapted or matched in the stop position of the transport element and to be straight in the transfer position of the transport element. Because the feeder roll of the sheet-processing machine is normally constructed straight in the direction of the sheet width, it is advantageous that the guide edge is correspondingly configured straight in the transfer position of the transport element, in order to permit correct and disruption-free transfer of the respective sheet to the feeder roll.
The transport element is preferably movable counter to or in the respective contour-adaptation or matching direction by a restoring spring element that is compressed or expanded by the pivoting of the transport element. Arranging one or more restoring spring elements which are operatively connected to the transport element ensures, in a relatively simple and particularly reliable manner, that the adapted or matching contour of the guide edge is canceled in the transfer position of the transport element by a pivoting angle-dependent movement or displacement of the transport element counter to the respective contour-adaptation or matching direction, because the respectively deformed segments of the transport element are reshaped, due to the displacement of the latter counter to the respective contour-adaptation or matching direction, when the adjusting device is not displaced correspondingly, forming a desired, straight contour of the guide edge.
In the transfer position of the transport element, the restoring spring element is advantageously compressed, the transport element is retracted and the contour adaptation or matching of the guide edge is canceled, while, in the stop position of the transport element, the restoring spring element is expanded, the transport element is extended and the contour of the guide edge is completely adapted or matched. A restoring spring element acting in this manner permits reliable and quick separation of the sheets, piled up to form a stack, in the feeder, and appropriate transport of the respectively topmost sheet from the stack to the feeder roll by the transport element.
The transport element is preferably formed as a continuous, pivotable flap, and the fixing device is constructed as a pivoting shaft for the flap. A transport element not formed from individual, separate segments but as a continuous flap can be mounted and adjusted in a relatively simple manner. In this case, a pivoting shaft formed as a fixing device helps to provide a particularly compact construction of the separating device.
Further advantageous refinements of the invention emerge from the description.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device for separating or singling sheets piled up to form a stack, in a feeder of a sheet-processing machine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: